An Analyzer used primarily at query time to wrap another analyzer and provide a layer of protection
which prevents very common words from being passed into queries.

For very large indexes the cost
of reading TermDocs for a very common word can be high. This analyzer was created after experience with
a 38 million doc index which had a term in around 50% of docs and was causing TermQueries for
this term to take 2 seconds.

QueryAutoStopWordAnalyzer(Version matchVersion,
Analyzer delegate,
IndexReader indexReader,
float maxPercentDocs)
Creates a new QueryAutoStopWordAnalyzer with stopwords calculated for all
indexed fields from terms with a document frequency percentage greater than
the given maxPercentDocs

QueryAutoStopWordAnalyzer(Version matchVersion,
Analyzer delegate,
IndexReader indexReader,
int maxDocFreq)
Creates a new QueryAutoStopWordAnalyzer with stopwords calculated for all
indexed fields from terms with a document frequency greater than the given
maxDocFreq